Mr Datena later told TV Cultura that he had attacked Mr Marcal because he had brought up old sexual harassment allegations against Mr Datena that were dismissed several years ago.
The decision by the Manhattan-based 2nd US Circuit Court of Appeals means the British socialite will remain in a Florida prison, where she is serving a 20-year sentence.
EU chief Ursula von der Leyen put Raffaele Fitto forward as one of six executive vice presidents who will serve as her key lieutenants in the European Union's executive body.
Bangladesh battled through civil unrest and violence last month - the result of a student-led movement against quota in government jobs - that forced then Prime Minister Sheikh Hasina to resign.
The attorney for the Southern District of New York, Damian Williams, said in a statement that the arrest stemmed from a sealed indictment filed by his office.